America’s problem with obesity is well known. And more and more cats and dogs are also suffering from obesity. Now veterinarians have found that another favorite animal is in danger of serious health problems due to being just too fat: horses.

Horses in Virginia were recently experiencing a big increase in cases of laminitis, a condition where the connective tissue between the hoof and bone falls apart. It’s what got the racehorse Barbaro. Researchers at the Virginia-Maryland Regional College of Veterinary Medicine theorized that the laminitis increase might be related to an epidemic of obesity, which could bring about chronic inflammation and other deleterious conditions. So they examined 300 horses randomly chosen on over a hundred farms during the summer of 2006. And they found that just over half, 51percent, were either overweight or obese. And for the same reasons as people—too many calories and too little exercise.

The horses may not be overeating, though. Modern pasture plant materials were themselves bred to help foraging animals, like cattle, pack the weight on faster. Looks like horses may have been cowed into becoming fat.